138
Fundamentals of Corrosion
Quite often, curing compounds are applied to fresh concrete as soon as
practical after the forms have been removed. These are liquid membranes
based on waxes, resins, chlorinated rubber, or other film formers, usually
in a solvent. Pretesting is necessary to determine whether or not they will
interfere with the coating to be applied.
Generally, they are added to concrete mixes in order to speed up or slow
down the cure, add air to the mix, or obtain other special effects that will not
interfere with surface treatments to improve durability. The concrete supplier can furnish specific data regarding the admixtures. If in doubt, try a
test patch of the coating material to be used.
TabLE 4.16
Brittle Points of Common Elastomers
Elastomer
Brittle Point
(°F)
(°C)
NR, IR
−68
−56
CR
−40
−40
SBR
−76
−60
NBR
−32 to −40
−1 to −40
CSM
−40 to −80
−40 to −62
BR
−68
−56
EA
−75
−60
EPDM, EPT
−90
−68
SEBS
−58 to −148
−50 to −100
Polysulfide SF
−60
−51
Polysulfide FA
−30
−35
AU
−85 to −100
−65 to −73
Polyamide No.
11
−94
−70
PE
−94
−70
TPE
−67 to −70
−55 to −60
SI
−75
−60
FSI
−75
−60
HFP
−80
−62
FKM
−25 to −75
−32 to −59
ETFE
−150
−101
ECTFE
−105
−70
FPM
−9 to −58
−23 to −50
Source: From Reference 17.